Typical applicators for dispensing adhesive may receive adhesive from a melter, and include positive displacement fluid dispensers that intermittently apply a flow of the adhesive to a substrate. The fluid dispensers actuate between an on cycle, during which adhesive is flowing through a nozzle of the dispenser, and an off cycle, during which adhesive is prevented from flowing through the nozzle of the dispenser. During the off cycle, unused adhesive can build up within the applicator, which leads to elevated pressures within the applicator. Upon commencing the next on cycle, the built-up adhesive within the applicator causes the adhesive to exit the dispenser nozzle at an inconsistent flow rate or a flow rate that is different than intended. This leads to adhesive pattern deformation on the substrate.
To remedy this issue, some applicators include recirculation hoses that redirect and transport unused adhesive back to the melter during the fluid dispenser off cycle. However, the use of a recirculation hose creates some drawbacks. Recirculation hoses prevent the dynamic control of the flow rate of the recirculated adhesive, which can decrease the accuracy of the flow of adhesive from the dispenser nozzle. Additionally, adhesive can harden and create char within the recirculation hose, which can flow downstream and clog the adhesive flow path. Further, recirculation hoses can be costly and require additional temperature control systems to maintain the flow of recirculated adhesive in a liquid state.
Therefore, there is a need for an applicator for dispensing adhesive that allows for dynamically managing and controlling the flow rate of recirculated adhesive.